Revolve Curve 360 degrees
You could just take a straight curve, right up the middle of your tree, bevel it,  and AltS edit the radius of the curve up its length. Or use half of your profile as a 'Taper' curve for another curve's bevel. (Both handy for bendy trees)
But the easiest move from your profile to its surface of revolution is to take half of it, (with its origin on the axis of rotation,) and give it a Screw modifier: